From Joe-Bob's handy-dandy reference:
(wikiedia...)
Normal magic squares exist for all orders
n ≥ 1 except
n = 2, although the case
n = 1 is trivial—it consists of a single cell containing the number 1
The constant sum in every row, column and diagonal is called the
magic constant or magic sum,
M. The magic constant of a normal magic square depends only on
n and has the value
For normal magic squares of order
n = 3, 4, 5, …, the magic constants are:
15, 34, 65, 111, 175, 260, …